Building a Redis-like In-Memory Database From Scratch in Rust

My “Why”: From Professional Coder to Rust Beginner

So, What is IronCache?

My “Aha!” Moments: The Key Concepts That Clicked

1. Finally Understanding Ownership in Practice

// This became the core of my shared state managementuse std::sync::{Arc, Mutex};// The shared database type, safe to pass across threadstype Db = Arc<Mutex<Storage>>;// In my main loop, I could give each new task a reference// to the same database without violating ownership rules.let db_clone = db.clone();tokio::spawn(async move {    // This background task can now safely access the shared state.    handle_client(socket, db_clone).await;});

2. The Elegance of Async Programming with Tokio

#[tokio::main]async fn main() -> Result<(), Box<dyn std::error::Error>> {    let listener = TcpListener::bind("127.0.0.1:6969").await?;    loop {        let (socket, _) = listener.accept().await?;        let db = db.clone();        // Spawn a new, independent task for each connection.        // The main loop immediately goes back to accepting more clients.        tokio::spawn(async move {            handle_client(socket, db).await;        });    }}

3. Making My Code Smarter with Enums and Pattern Matching

// An enum that carries the data for each commandpub enum Command {    Get { key: String },    Set { key: String, value: String, expiry: Option<Duration> },    // ... more commands}// Pattern matching makes handling commands so clean and safe.// The compiler ensures I handle every possible command variant.match command {    Command::Get { key } => handle_get(key, &db).await,    Command::Set { key, value, expiry } => handle_set(key, value, expiry, &db).await,    // ...}

4. Effortless Serialization with Serde

use serde::{Serialize, Deserialize};#[derive(Serialize, Deserialize, Debug)]pub struct Storage {    data: HashMap<String, StoreValue>,    // I can even tell Serde to ignore runtime-only fields!    #[serde(skip)]    dirty: bool,}

5. Error Handling That I Couldn’t Ignore

// My parser returns a Result, forcing the caller to handle parse errors.pub fn parse(buffer: &[u8]) -> Result<Command, ParseError> {    match parts.as_slice() {        ["SET", key, value] => Ok(Command::Set { /* ... */ }),        _ => Err(ParseError::UnknownCommand),    }}// In my main loop, I can handle it cleanly.let command_result = Command::parse(&buffer);match command_result {    Ok(command) => execute_command(command, &db).await,    Err(e) => format!("ERROR: {:?}\n", e),}

Features I’m Most Proud Of

What’s Next?

Final Thoughts